Sequential Hydrocarbon C—H Bond Activations by 16-Electron Organometallic Complexes of Molybdenum and Tungsten

Abstract

Cp*M(NO)(hydrocarbyl) 2 complexes (Cp* = η 5 -C 5 Me 5 ) of molybdenum and tungsten exhibit hydrocarbyl-dependent thermal chemistry. Thus, gentle thermolysis of appropriate Cp*M(NO)(hydrocarbyl) 2 precursors (M = Mo, W) results in the loss of hydrocarbon and the transient formation of 16-electron Cp*M(NO)-containing complexes such as Cp*M-(NO)(alkylidene), Cp*M(NO)(η 2 -benzyne), Cp*M(NO)(η 2 -acetylene), and Cp*M(NO)(η 2 -allene). These intermediates effect single, double, or triple activation of hydrocarbon C-H bonds intermolecularly, the first step of these activations being the reverse of the transformations by which they were generated. This Chapter summarizes the various types of C-H activations that have been effected with these organometallic nitrosyl complexes to date and presents some of the results of kinetic, mechanistic, and theoretical investigations of these processes.